Hammer actuating mechanism



March 11, 1952 A. R. FlLlPPl HAMMER ACTUATING MECHANISM 2 SHEETS-SHEET 1 Filed March 20, 1950 JNVENTOR. ALDO ROBERT F/L'IPPI A TTORNEY March 11, 1952 A. R. FlLlPPl HAMMER ACTUATING MECHANISM 2 SHEETS-SHEET 2 Filed March 20, 1950 anvil-VIII INVENTOR.

ALDO ROBERT F/L/PP/ ATTORNEY Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE HAMMER ACTUATIN G MECHANISM Aldo Robert Filippi, Redwood City; Calif.

Application March 20, 1950, Serial No. 150,790

5 Claims. (Cl. -147) This invention relates to an improved hammer actuating mechanism.

The present invention provides an electrically operated hammer for driving nails, spikes or the like. The hammer is actuated downwardly with considerable force by means of a heavy compression spring and its upward return movement is effected by a motor operated cam. The operation of the hammer is controlled by means of an easily manipulated hand grip, thereby making it possible to commence or discontinue the up and down movement of the hammer whenever desired. The hammer is intermittently released for instantaneous movement in a downward direction by a circularly moving cam which is so constructed and arranged that it slowly raises the hammer after its striking operation is completed and then abruptly releases it so the charged tension spring may again actuate it downwardly.

The primary object of the present invention is to provide an electrically operated hammer of the kind characterized, embodying novel means for controlling its operation.

Other and further objects of my invention will be pointed out herein, or will be indicated in the appended claims, or will be obvious to one skilled in the art upon an understanding of the present disclosure. For the purpose of this application I have elected to show herein certain forms and details of an electric hammer representative of my invention; it is to be understood, however, that the embodiment of my invention herein shown and described is for the purpose of illustration only, and that therefore it is not to be regarded as exhaustive of the variations of the invention.

In the accompanying drawings:

Fig. 1 is a front elevational view of an electric hammer embodying my invention;

Fig. 2 is a plan view of the same;

Fig. 3 is a sectional view taken vertically through the cam wheel and showing the cam arm in an elevated position;

Fig. 4 is a sectional view taken on the line 4---4 of Fig. 2, showing portions of the cam wheel broken away;

Fig. 5 is a diagrammatic detailed view taken on the line 5-5 of Fig. 3, showing the position of the cam when the hammer arm is in a raised position;

Fig. 6 is a detailed sectional view showing .portions of the hammer arm and its associated stop wheel; and

Fig. 7 is a sectional view taken on the line 1-1 of Fig. 4.

Referring to the drawings the numeral I designates a supporting frame or base which is mounted on spherical members 2 or other similar means which facilitates the movement of the machine from place to place. Pivotally supported between 'its'ends on a shaft 3 that is journaled on trunnionsl is a hammer arm 5 which is arranged for'up and down pivotal movement. The hammer arm 5 carries a hammer 6 at its outer end which is adapted to travel through an arcuate path when moving upwardly and downwardly during a nail or spike driving operation. For illustration purposes a nail holding device I is shown in aposition for striking engagement by the hammer. Aheavy helical compression spring 8 is arranged to urge the rear end of the hammer arm '5 upwardly and the hammer 6 downwardly. The spring 8 is mounted on and positioned between two spaced discs 9, the lower of which is provided with a socket for receiving a ball l0 carried by an adjusting screw II. The adjusting screw is threaded through an opening in the base I, and an enlargement at its lower end provides convenient means for turning it to adjust the tension of the spring 8. The upper plate 9 with which the spring engages is provided with a spherical protuberance l2 which fits in a socket formed in a boss carried at the rear end of the hammer arm 5. The 'ball and socket arrangements above described make it possible for the spring 8 to automatically adjust its position as the rear end of the hammer arm moves up and down. The hammer arm 5 is shown as comprising three integrally joined sections which are notin alignment, but such a shape is not essential to the operation of the machine since the arm may be straight, curved or otherwise suitably shaped. The helical tension spring 8 exerts sufficient pressure in an upward direction on the rear end of the hammer arm 5 to cause the hammer 6 to move downwardly with a considerable striking force when the said arm is released from its raised position.

Supported on trunnions l3 secured to the base I is a drive shaft I 4 which is operatively connected by suitable reduction gear and shaft connections l5 to the drive shaft it of an electric motor H. The shaft l4 rotates continuously in a counterclockwise direction (Figs. 4 and 5). Keyed to the drive shaft I4 is a cam wheel [8 which extends vertically alongside the hammer arm 5. Loosely mounted on the drive shaft I4 is a cam l9 which is formed with an arcuate slot 20 within which a pin 2| secured eccentrically to the cam wheel l8 loosely fits. The arcuate slot 20 in the cam I9 is concentrically arranged with respect to the drive shaft I4 and the cam wheel IS. The cam is is arranged alongside the cam wheel la in a position underlying and engaging with the hammer arm 5. As the cam wheel l8 rotates the pin 2| engaging with the leading end of the arcuate slot 20 carries the cam IS in a circular counterclockwise direction (Figs. 4 and 5). The cam is so shaped that it slowly raises the forward portion of the hammer arm 5 and thehammer 6 to elevated positions preparatory to their downward striking operation. The cam l9 and its arcuate slot 20 are so shaped that when the cam reaches a position in which the hammer arm 5 is at the upper extremity of its upward movement, it will be swung at an accelerated speed in a counterclockwise direction by the downward pressure of the hammer arm thereon. By reason of the shape and position of the slot in the cam I9, the said cam is free to move with acceleratedspeed-after its trailing end reaches a positionwhere it no longer supports the hammer arm. When the cam [9 thus assumes a position in which itno longer restrains the hammer arm 5 and the hammer 6 from being moved downwardly by the compression spring 8, the said hammer arm and hammer immediately commencertheir.downward'stroke. This occurs after thecam has been carried slightly beyond the positionshown in Fig. 5. The-cam 19 being free torotate independently of the shaft l4 drops downwardly to a positionin which it does not interferet with the completion of the downward stroke: of the hammer arm and hammer. The continued: rotation of the cam wheel l8 carries the pin 2| through the length of the arcuate slot 20 in the cam 9; and-withthe said pin again engaging with the leading end of the arcuate slot the cam isrotated to a position where it again exerts an upwardli'fting pressure on the hammer arm".

The operation of the hammer is controlled by the mechanism now to'be described.

Secured'torthe-drive shaft Hi ls a hammer stop wheel .22 which is soconnected to' the said shaft by a: longitudinal key-way and key that it may be? shifted: backand forth toward-and away from the cam wheel iii; The hammer stop wheel 22 is. formed with an annular peripheral groove or channel 23: within which a downwardly projecting pin 2t secured to the hammer arm 5 may become positioned. The pin 24 isadmitted to the peripheral channel 23 through an opening or slot 25 (Fig. 2) in the inner peripheral flange of the hammer stopwheel- 22 when the latter is shifted toward the cam wheel Ill. The pin 24 may enter the channel 23 of the hammer stop wheel 22 when the hammer arm 5 has reached the height where the said pin is horizontally aligned with the slot 25- and when the hammer stop wheel.- is suitably shifted along the drive shaft- 13- to allow the said pin to enter the said channel through the-said slot. The entry of the pin 24-- throughthe? slot- 25 into the peripheral channel 23 of the hammer stop wheel 22' is effected when the said wheel has rotated sulficie-ntly to'bring' the: slot into a position directly opposite the said pin. When the pin 24 has become positioned in the peripheral channel 23 of the hammer stop Wheel 22 it rides on the periphery of the said wheel and thereby holds the hammer arm 5 in an inactive raised position. By shifting the hammer stop wheei 22 in the opposite direction and away from the cam wheel iii the pin 24 of" the hammer arm moves through theslot25= (Figs. 2 and 6); to a disengaging position with respect to the periphery of the hammer stop wheel, thereby allowing the hammer arm 5 and the hammer B to again resume their up and down movement.

The hammer stop wheel 22 is formed with a hub portion 22' which is also formed integrally with a circular flange 26, the said flange being suitably spaced from the hammer stop wheel to permit the forked endof a lever 21 to be positioned between the said wheel and the flange. The forked end of the lever 21 rests at one end on the hub portion 22 of the hammer stop wheel 2-2 and its-opposite end is engaged and supported by a stop 28 (Fig. 2) secured on the motor I! or on the frame or base I. A coiled compression spring 29 arrangedbetween a non-shiftable stop collar 3% and the flange urges the said flange, the hub'portion 22' and the hammer stop wheel 2'2 toward the cam wheel 13. Pivotally mounted between its ends as at 3i on a supporting member 32 secured on the base i, is'a control lever mem ber 33. The upper end of the controllever 33 is connected by means 34 to the forked lever 2'! while its lower endisconnected by a cable 35 to one end of a hand grip lever 38. The hand grip lever is pivoted at one end as at B'l-on a stationary support 33. By. pulling the hand lever 36 outwardly in a directionaway from the base i the forked end'of the lever 21 is moved against the pressure of the spring, 2E1 in a direction away from the cam wheel. i8, thereby eXertinga pressure in the same direction on the flange 26. The said he hub portion 22' and the hammer stop wheel 22 are all shiitedalong the drive shaft 53 in the same direction, thereby allowing. the hammer arm pin 26 to be released from engagement with the periphery of. the said hammer stop wheel. The hammer. arm 5 and thehammer B thereupon resume their up and down movement. When the operation. of the hammer is to be again discontinued the hand grip lever 38 is released, thereby allowingthe compression spring 29 to return the cam stop wheel 22. to a position whereby the hammer arm pin 24 may againenter the annular peripheral groove 23 and ride on the periphery of the said cam stop wheel.

What I claim is:

1. In an electrical hammer, a rigid hammer arm mounted between its ends for pivotal movement about a substantially horizontal axis, a hammer carried onv the forward end of the arm, spring means urging the forward end of the hammer arm and the hammer downwardly, a drive shaft extending beneath the hammer arm, a cam mounted on the drive shaft and arranged beneath and in engagement with the hammer arm, means coupled with the cam and actuated by the drive shaft for rotating the cam, whereby the forward end of the hammer arm and the hammer may be actuated upwardly against the pressure of the spring, and control means for releasably holding the forward end of the hammer arm and the hammer in a raised position.

2. In an electric hammer, a hammer arm carrying a hammer at its forward end, the said hammer arm being arranged to swing about a substantially horizontal pivot, spring means urging the forward portion of the hammer arm and the hammer downwardly, a drive shaft, a cam Wheel keyed to the drive shaft, a cam loosely mounted on. the drive shaft adjacent the cam wheel and having. an arcuate concentric slot, and a projecting pin carried eccentrically by the cam wheel and arranged in the slot, the said cam having a cam surface arranged to engage with drive shaft, a cam loosely mounted on the drive' shaft, means operatively connecting the cam and the cam. wheel, the said cam having a cam surface arranged to engage with the underneath side of the hammer arm, and the said cam being constructed and arranged to raise the forward end portion of theha'mmer arm to a predetermined position and then to abruptly disengage said hammer arm.

4. In an electric hammer, a hammer arm having a hammer secured to its forward end, the said hammer arm being pivotally mounted to swing up and down, spring means urging the forward end portion of the hammer arm and the hammer downwardly, a drive shaft, a cam wheel keyed to the drive shaft, a cam loosely mounted on the driveshaft and coupled to the cam wheel, the said cam being arranged to raise the forward end portion of the hammer arm to a predetermined height against the pressure of the spring means and then abruptly release the said arm, and control means for intercepting and releasably holding the hammer arm while in its said raised position.

5. In an electric hammer, a hammer arm having a hammer carried on its forward end portion and having also a downwardly projecting member, the said hammer arm being mounted between its ends for up and down pivotal movement, spring means engaging the rear end portion of the hammer arm for urging the forward end portion thereof and the hammer downwardly, a drive shaft, a cam wheel keyed to the drive shaft, a cam loosely mounted on the drive shaft and coupled to the cam wheel, the said cam being constructed and arranged to engage with and raise the forward end portion of the hammer arm to a predetermined height against the pressure of the spring means and then'abruptly release thesaid arm, a rotatable stop wheel keyed to but slidable back and forth on the drive shaft, the said stop wheel having annular means at its periphery" for receiving and supporting the downwardly projecting member of the" hammer arm, whereby'the operation of the hammer arm may be discontinued, a spring urging the stop wheel toward the hammer arm, and hand con trolled means for shifting the stop Wheel against the pressure of the spring to a position whereby the projecting member of the hammer arm is free ofthe supporting means of the stop wheel.

ALDO ROBERT EILIPPI.

REFERENCES CITED The following references are of record in the file of this" patent:

UNITED STATES PATENTS 1,822, 2 2 Garllus Spt. 3, 1931 

